This invention relates to a device for transporting a semi-fluid mass such as concrete mix and more particularly, to a concrete placing boom device.
In the past, a variety of equipment for distributing concrete mix has been developed. Buckets of concrete mix have been lifted by cranes, and concrete mix has been distributed by conveyor systems such as those disclosed in U.S. Pat. No. 3,343,651, U.S. Pat. No. Re. 29,110 and U.S. Pat. No. Re. 26,298. A primary goal of such equipment is to transport concrete mix rapidly and continuously into a concrete pour area, with accurate placement, so that a unified and strong concrete structure may be poured.
Recently, concrete pumps have been employed to pump concrete mix through pipelines into concrete pour areas. Utilized with such pumps and pipelines are boom devices. Generally, concrete placing boom devices have been mounted on concrete mixing trucks that are positioned adjacent concrete pour areas. While such devices are useful, the trucks are incapable of traveling directly into some concrete pour areas during pouring, because of the reinforcing steel used in the pour area. The use of the booms is thus limited, because when the concrete pour area is large, the boom cannot reach far enough into the concrete pour area to distribute concrete mix to the center thereof. A further disadvantage of many truck-mounted boom devices is that they elevate concrete mix to heights of fifty feet or more before moving or placing the mix the desired horizontal distances. They thus unnecessarily expend large amounts of energy elevating the concrete mix.
Unfortunately, concrete conveyor devices are not readily convertible to utilization with concrete piping and concrete pumps. This is because concrete flowing inside a pipeline creates high magnitude stresses on joints and bearings, above and beyond those stresses encountered in conveyor systems.